Conventionally, a resin-sealed type and a sealed and airtight type are known as a package utilized for a semiconductor element.
The resin-sealed type semiconductor device has a structure which embedded directly the semiconductor element mounted in a leadframe in the resin by using a transfer mold etc., and is widely used by the advantage, such as low cost, being suitable for mass production, and a miniaturization being possible.
The sealed and airtight type semiconductor device has a structure which performed in hollow airtight maintenance of the semiconductor element mounted on a base substance composed of conductive materials, such as copper. Although the cost is higher compared with the resin-sealed type semiconductor device, the sealed and airtight type semiconductor device is used when high reliability is required because of excellent in airtightness.
In the sealed and airtight type package, it is known about an example of package mounting a semiconductor element directly on the heat radiation body composed of metal, and including input/output terminal units having convex feed through structure.
When two frequencies are inputted into one high frequency amplifier, the difference frequency component occurs. When the difference frequency is several MHz, the voltage of output terminal and the voltage of chip end face are smoothed by connecting a capacitor which is not less than 100 micro F near an RF output terminal.
However, when the difference frequency is several hundreds of MHz, the capacitor connected near the RF output terminal cannot smooth the voltage of the chip end face, since a matching circuit intervenes between the chip end face and the capacitor.